JP4260973B2

JP4260973B2 - Freshness measurement method

Info

Publication number: JP4260973B2
Application number: JP09028599A
Authority: JP
Inventors: 勝史佐藤; 秀和池崎; 寛駒井
Original assignee: 株式会社インテリジェントセンサーテクノロジー
Priority date: 1999-03-30
Filing date: 1999-03-30
Publication date: 2009-04-30
Anticipated expiration: 2019-03-30
Also published as: JP2000283953A

Description

【０００１】
【発明の属する技術分野】
本発明は飲食物の鮮度を測定する方法に係り、特に味覚センサを用いて飲食物の鮮度を測定する方法に関する。
【０００２】
【従来の技術】
飲食物の鮮度の測定は、化学分析等で行われている例があるが、測定時間が掛かることや測定感度の点で満足できるものではなく、主に官能検査で行われている。
【０００３】
【発明が解決しようとする課題】
しかし、官能検査は、識別力に個人差があることや評価の数値化に難があり客観性に乏しいといった問題点がある。
この発明の目的は、前述の問題点を解決して、測定時間が短くて済む、感度が官能検査に劣らない、評価が数値化できる飲食物の鮮度測定方法を提供することである。
【０００４】
【課題を解決するための手段】
前述の課題を解決するために、この発明の鮮度測定方法は、請求項１に記載のものは、両親媒性物質を含む分子膜を有する味覚センサを用いて飲食物の鮮度を測定する鮮度測定方法であって、鮮度の基準となる第一の飲食物を所定の条件で保存する段階と、前記所定の条件で保存された前記第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値を得る段階と、鮮度を測定する対象である第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第二の測定値を得る段階と、前記第一の測定値と前記第二の測定値の差に基づいて前記第二の飲食物の鮮度を求める段階とを含んでいる。
【０００５】
請求項２に記載のものは、両親媒性物質を含む分子膜を有する味覚センサを用いて飲食物の鮮度を測定する鮮度測定方法であって、鮮度の基準となる第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値を得て該第一の測定値を記憶する段階と、鮮度を測定する対象である第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第二の測定値を得る段階と、記憶された前記第一の測定値と前記第二の測定値の差に基づいて前記第二の飲食物の鮮度を求める段階とを含んでいる。
【０００６】
請求項３に記載のものは、両親媒性物質を含む分子膜を有する味覚センサを用いて飲食物の鮮度を測定する鮮度測定方法であって、鮮度の基準となる第一の飲食物を所定の第一の条件で保存する前に該第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値を得る段階と、鮮度を測定する対象である第二の飲食物を第二の条件の下に置く前に該第二の飲食物の溶液に味覚センサを浸漬してその味を測定し第二の測定値を得る段階と、前記第一の飲食物を所定の第一の条件で保存する段階と、前記第一の条件で保存された前記第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第三の測定値を得る段階と、前記第二の条件の下に置かれた第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第四の測定値を得る段階と、前記第一の測定値と前記第二の測定値の差と前記第三の測定値と前記第四の測定値の差との差に基づいて前記第二の飲食物の鮮度を求める段階とを含んでいる。
【０００７】
請求項４に記載のものは、両親媒性物質を含む分子膜を有する味覚センサを用いて飲食物の鮮度を測定する鮮度測定方法であって、測定対象である飲食物の被測定溶液を複数準備する段階と、該複数の被測定溶液をそれぞれ異なる温度で所定時間保存する段階と、該所定時間保存された複数の被測定溶液のそれぞれについて前記味覚センサを浸漬してその味を測定し、該複数の被測定溶液それぞれの測定値を得る段階と、得られた複数の前記測定値と前記温度とに関連した回帰曲線を求める段階と、該回帰曲線に基づいて所望温度における鮮度の補正値を得る段階と、所望時間後の所望温度における鮮度の補正値を、回帰曲線に基づいて得られた所望温度における鮮度の補正値に前記所望時間と前記所定時間の比の値を掛けて、求める段階と、鮮度の基準となる第一の飲食物を所定の第一の条件で保存する前に該第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値を得る段階と、鮮度を測定する対象である第二の飲食物を第二の条件の下に置く前に該第二の飲食物の溶液に味覚センサを浸漬してその味を測定し第二の測定値を得る段階と、前記第一の飲食物を所定の第一の条件で保存する段階と、前記第一の条件で保存された前記第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第三の測定値を得る段階と、前記第二の条件の下に置かれた第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第四の測定値を得る段階と、前記第一の測定値と前記第二の測定値の差と前記第三の測定値と前記第四の測定値の差との差および前記補正値に基づいて前記第二の飲食物の鮮度を求める段階とを含んでいる。
【０００８】
【発明の実施の形態】
本発明の実施の形態を説明する前に本発明に用いることとした味覚センサについて説明をする。
本願出願人は、先に他と共同して「味覚センサ及びその製造方法」の発明につき特許出願をし（特開平3-54446 ）、その明細書及び図面によって、ある種の高分子重合体の表面マトリックス内に特定の分子配列をもって収納されたいわゆる脂質性分子群が、基本味と呼ばれる塩味、酸味、苦味、甘味に対して、感度を示すセンサとなることを示した。しかも、この種のセンサは、人間の五感の一つである味覚に代わり、味を測定できるものであることを示した。
【０００９】
高分子重合体は、例えばポリ塩化ビニル（ＰＶＣ）であり、それにジオクチルフェニルフォスフォネート（DOPP）のような可塑剤と脂質とを概ね２：３：１の重量比で混合したものをテトラヒドロフラン（ＴＨＦ）に溶融し、平底の容器に移して、板上で室温に三日間保持して、ＴＨＦを揮発させ、脂質膜すなわち脂質がＰＶＣの表面マトリックス内に収納された脂質性分子膜を得た。膜の厚さは約２００μｍである。
【００１０】
脂質性分子膜の模式図を、化学物の設計法で使われている表現方法で表わしたものが図８である。脂質性分子２のうち円で示した球状部は親水基ａすなわち親水性部位ａであり、それから原子配列が長く延びる炭化水素の鎖構造ｂ（例えばアルキル基）がある。図ではいずれの場合も２本の鎖が延びて一つの分子を表わしており、全体で分子群を構成している。この炭化水素の鎖の部分は、疎水性部位ｂである。このような脂質性分子群３が、膜部材４の表面のマトリックス５（表面の構造、平面的なひろがりをもったミクロな構造）の中に、一部はマトリックス内部に溶け込ませた形（例えば図８の２′）で収容されている。これらのような構造を持つ分子膜の原料となる脂質の例を表１に示す。
【００１１】
【表１】

【００１２】
これらの脂質膜を用いたセンサプローブを用意する。
図９は前述のようにして得られた脂質膜１をセンサプローブ６に加工した概略構成を示す断面図である。基材７として外形８mm、長さ５５mm、肉厚１mm、のポリ塩化ビニルの円筒を用いる。該円筒７の先端部７ａを約６０度の角度でカットする。該カットされた先端部７ａに、その開口部７ｂを塞ぐように脂質膜１を、ＴＨＦにＰＶＣを溶解したものを接着剤として張り付ける。直径０．５mmの銀線の先を螺旋状に巻いたものを該円筒７の上部から挿入し電極８とする。緩衝層９として電解液（３．３mol/l の濃度の塩化カリウム溶液）を前記電極８の螺旋部分に８ｂが浸るところまで充填する。
【００１３】
前記センサプローブを用いた味の測定系を図１０に示す。
被測定溶液１１はビーカーのような容器１２に入れる。被測定溶液１１中に前記センサプローブ６を入れた。この図では１本のセンサプローブであるが、マルチチャンネルで測定する場合は脂質の異なる脂質膜を有する（味に対する応答の異なる）複数本のセンサプローブを用いる。使用前に、塩化カリウム１mmol/l水溶液で電極電位を安定化した。測定の基準となる電位を発生する電極として参照電極１３を用意し、それを被測定溶液１１に入れる。センサプローブ６と参照電極１３とは所定の距離を隔てて設置する。参照電極１３の表面は、緩衝層１４として飽和塩化カリウム溶液を寒天で固化したもので覆ってある。
【００１４】
脂質膜１からの電気信号は、図１０のリード線１５によってバッファ増幅器１７導かれる。バッファ増幅器１７の出力は、Ａ／Ｄ変換器１８に加えられる。参照電極１３からの電気信号もリード線１６を介してＡ／Ｄ変換器１８に加えられ、脂質膜１からの電位との差をディジタル信号に変換する。このディジタル信号はマイクロコンピュータ１９で適当に処理され、またＸ−Ｙレコーダ２０で表示される。
【００１５】
次に、味覚センサを用いた測定の手順の一例を図１１に基づいて説明する。
Ｓ１基準液のセンサ電位V01 を測定する。
バッチ式測定（被測定溶液を例えばビーカー等にとって行う測定の方式）の場合、味覚センサを空中に一定回数出し入れた後、再度基準液のセンサ電位V01 を測定する。フロー式測定（例えば味覚センサのセットされた測定用のパイプに被測定溶液及び基準液をそれぞれ流して行う測定の方式）の場合、味覚センサに基準液一定時間流した後、再度基準液のセンサ電位V01 を測定する。
Ｓ２所定時間被測定溶液Siにセンサを浸漬すると共に被測定溶液Siのセンサ電位Viを測定する。所定時間を設定するのは各被測定溶液Siで吸着の条件を同じにするためである。
Ｓ３被測定溶液Siの測定結果△Vi=Vi-V01 を算出する。その後連続して被測定溶液を測定する場合はＳ１へ進む。
【００１６】
なお、脂質は両親媒性物質の一種であり、表２に示す脂質以外の両親媒性物質も脂質の代わりに利用できる。
【００１７】
【表２】

【００１９】
以上のような両親媒性物質の分子膜を備えた味覚センサを用いることにより飲食物の鮮度を測定する事が出来る。
【００２０】
以下、本発明の実施の形態を図１〜４に基づいて説明する。
図１は、本発明の鮮度測定方法の第一の実施の形態を示す流れ図であり、請求項１に対応するものである。
Ｓ１１鮮度の基準となる第一の飲食物を所定の条件で保存する段階である。
第一の飲食物は鮮度の基準となる値を提供するために保存される飲食物である。したがって、前記所定の条件は、時間が経過しても、第一の飲食物の味がなるべく変化しないような条件、温度なら例えば０℃〜５℃、である。
Ｓ１２前記所定の条件で保存された前記第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値Ｓt を得る段階である。
第一の測定値Ｓt は、鮮度の基準となる値である。
Ｓ１３鮮度を測定する対象である第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第二の測定値Ｓi を得る段階である。
Ｓ１４前記第一の測定値と前記第二の測定値の差に基づいて前記第二の飲食物の鮮度を求める段階である。
【００２１】
ここで、第一の実施の形態の鮮度測定方法による実験について述べる。
測定対象はスポーツドリンクとして市販されている缶入りの飲料である。味覚センサは、表４に示す脂質をそれぞれ含む脂質膜８種類を用いた８チャンネル（１ｃｈ〜８ｃｈ）の味覚センサを使用した。
【００２２】
【表４】

【００２３】
基準液は鮮度の基準となるスポーツドリンクと同じ条件で保存されたスポーツドリンクを用いた。保存は冷蔵庫で行い、温度は０℃である。測定対象のスポーツドリンクは、温度３０℃の条件下に１週間置かれたもの、同じく２週間置かれたもの、温度５０℃の条件下に１週間置かれたもの、同じく２週間置かれたものの４種類である。
【００２４】
測定手順は次のとおりである。
１）保存液（基準液と同じもの）に味覚センサをほぼ１０時間浸漬する。
２）基準液（洗浄用）に味覚センサを１０回出し入れし、洗浄する。
３）基準液（測定用）に味覚センサを浸漬し、１０秒後に味覚センサの電位を測定し、測定値をＶ0 とする。
４）手順２）、３）を２回以上繰り返し、測定ごとに今回の測定値Ｖ0 と前回の測定値Ｖ0 の差が０．３ｍＶ以下かどうかを判断し、０．３ｍＶ以下（つまりＶ0 が安定したら）であれば、手順５）へ進む。
５）所定の条件で保存された鮮度の基準となるスポーツドリンク（洗浄用）に味覚センサを１０回出し入れし、洗浄する。
６）所定の条件で保存された鮮度の基準となるスポーツドリンク（測定用）に味覚センサを浸漬し、１０秒後に味覚センサの電位Ｓt を測定する。
７）測定対象であるスポーツドリンク（洗浄用）に味覚センサを１０回出し入れし、洗浄する。
８）測定対象であるスポーツドリンク（測定用）に味覚センサを浸漬し、１０秒後に味覚センサの電位Ｓi を測定する。
９）手順２）〜８）を所定の回数繰り返す。
【００２５】
このようにして得られた測定値を主成分分析にかけると図５のような結果が得られた。図５で、ＰＣ１は第一主成分、ＰＣ２は第二主成分をそれぞれ表す。
３０℃の条件下と５０℃の条件下では、鮮度に対応するポイントＰ31，Ｐ32，Ｐ51，Ｐ32が時間の経過に従って、鮮度の基準となるポイントＰ0 から遠ざかって行くことが分かる。また、遠ざかる方向が異なることから、３０℃の条件下と５０℃の条件下では劣化の質が異なることが分かる。
【００２６】
図２は、本発明の鮮度測定方法の第二の実施の形態を示す流れ図であり、請求項２に対応するものである。
Ｓ２１鮮度の基準となる第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値Ｓt を得て該第一の測定値Ｓt を記憶する段階である。
第一の飲食物は鮮度の基準となる値を提供するための飲食物であり、第一の測定値Ｓt は鮮度の基準となる値である。第二の実施の形態では、第一の実施の形態のように、第一の飲食物を所定の条件で保存することを要しない。
Ｓ２２鮮度を測定する対象である第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第二の測定値Ｓi を得る段階である。
Ｓ２３記憶された前記第一の測定値と前記第二の測定値の差に基づいて前記第二の飲食物の鮮度を求める段階である。
【００２７】
図３は、本発明の鮮度測定方法の第三の実施の形態を示す流れ図であり、請求項３に対応するものである。
Ｓ３１鮮度の基準となる第一の飲食物を所定の第一の条件で保存する前に該第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値Ｓt を得る段階である。
第一の飲食物は鮮度の基準となる値を提供するために保存される飲食物である。したがって、前記所定の第一の条件は、時間が経過しても、第一の飲食物の味がなるべく変化しないような条件、温度なら例えば０℃〜５℃、である。
第一の測定値Ｓt は、鮮度の基準となる値である。
Ｓ３２鮮度を測定する対象である第二の飲食物を第二の条件の下に置く前に該第二の飲食物の溶液に味覚センサを浸漬してその味を測定し第二の測定値Ｓa を得る段階である。第二の条件は、例えば、第二の飲食物が輸送されたり、倉庫に保管されたり、店頭に並べられたりするときの温度等の条件である。
Ｓ３３前記第一の飲食物を所定の条件で保存する段階である。
Ｓ３４前記第一の条件で保存された前記第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第三の測定値Ｓt'を得る段階である。
Ｓ３５前記第二の条件の下に置かれた第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第四の測定値Ｓa'を得る段階である。
Ｓ３６前記第一の測定値と前記第二の測定値の差と前記第三の測定値と前記第四の測定値の差との差｛（Ｓa'−Ｓt'）−（Ｓa −Ｓt ）｝に基づいて前記第二の飲食物の鮮度を求める段階である。
【００２８】
この方法によれば、飲食物の製造ロットの間に鮮度の測定に影響するような味の差があるときでも、全ロットについて第一の飲食物を保存する必要はなく、いずれかのロットの飲食物を代表として保管すれば足りる。ロット間の味の差は｛（Ｓa'−Ｓt'）−（Ｓa −Ｓt ）｝の演算をすることで吸収される。
【００２９】
ここで、第三の実施の形態の鮮度測定方法による実験について述べる。
測定対象は缶入り緑茶である。味覚センサは、前述の表４に示す脂質をそれぞれ含む脂質膜８種類を用いた８チャンネル（１ｃｈ〜８ｃｈ）の味覚センサである。基準液は鮮度の基準となる緑茶と同じ条件で保存された緑茶を用いた。保存は冷蔵庫で行い、温度は１℃である。
【００３０】
測定手順は次のとおりである。
１）保存液（基準液と同じもの）に味覚センサをほぼ１０時間浸漬する。
２）基準液（洗浄用）に味覚センサを１０回出し入れし、洗浄する。
３）基準液（測定用）に味覚センサを浸漬し、１０秒後に味覚センサの電位を測定し、測定値をＳt とする。
４）手順２）、３）を２回以上繰り返し、測定ごとに今回の測定値Ｓt と前回の測定値Ｓt の差が０．３ｍＶ以下かどうかを判断し、０．３ｍＶ以下（つまりＳt が安定したら）であれば、手順５）へ進む。
５）測定対象である緑茶（洗浄用）に味覚センサを１０回出し入れし、洗浄する。
６）測定対象である緑茶（測定用）に味覚センサを浸漬し、１０秒後に味覚センサの電位Ｓa を測定する。
７）３０日後に、手順２）〜８）を繰り返して、基準液の測定値Ｓt'と測定対象である緑茶の測定値Ｓa'を得る。測定対象の緑茶は、３０日の間、温度５０℃の条件（第二の条件）下に置かれる。
緑茶の鮮度は｛（Ｓa'−Ｓt'）−（Ｓa −Ｓt ）｝と相関が高く、この値を鮮度の目安とすることができる。
【００３１】
図４は、本発明の鮮度測定方法の第四の実施の形態を示す流れ図であり、請求項４に対応するものである。
Ｓ４１測定対象である飲食物の被測定溶液を複数準備する段階である。
Ｓ４２該複数の被測定溶液をそれぞれ異なる温度で所定時間保存する段階である。
Ｓ４３該所定時間保存された複数の被測定溶液のそれぞれについて前記味覚センサを浸漬してその味を測定し、該複数の被測定溶液それぞれの測定値を得る段階である。
Ｓ４４得られた複数の前記測定値と前記温度とに関連した回帰曲線を求める段階である。
Ｓ４５該回帰曲線に基づいて所望温度における鮮度の補正値を得る段階である。
Ｓ４６所望時間後の所望温度における鮮度の補正値を、回帰曲線に基づいて得られた所望温度における鮮度の補正値に前記所望時間と前記所定時間の比の値を掛けて、求める段階である。
【００３２】
Ｓ４７鮮度の基準となる第一の飲食物を所定の第一の条件で保存する前に該第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第一の測定値Ｓt を得る段階である。
第一の飲食物は鮮度の基準となる値を提供するために保存される飲食物である。したがって、前記所定の第一の条件は、時間が経過しても、第一の飲食物の味がなるべく変化しないような条件、温度なら例えば０℃〜５℃、である。
第一の測定値Ｓt は、鮮度の基準となる値である。
Ｓ４８鮮度を測定する対象である第二の飲食物を第二の条件の下に置く前に該第二の飲食物の溶液に味覚センサを浸漬してその味を測定し第二の測定値を得る段階である。第二の条件は、例えば、第二の飲食物が輸送されたり、倉庫に保管されたり、店頭に並べられたりするときの温度等の条件である。
Ｓ４９前記第一の飲食物を所定の条件で保存する段階である。
Ｓ５０前記第一の条件で保存された前記第一の飲食物の溶液に味覚センサを浸漬してその味を測定し第三の測定値を得る段階である。
Ｓ５１前記第二の条件の下に置かれた第二の飲食物の溶液に前記味覚センサを浸漬してその味を測定し第四の測定値を得る段階である。
Ｓ５２前記第一の測定値と前記第二の測定値の差と前記第三の測定値と前記第四の測定値の差との差および前記補正値に基づいて前記第二の飲食物の鮮度を求める段階である。
【００３３】
図６は、本発明の鮮度測定方法での各測定値の関係を示す図である。
図で、縦軸は味覚センサの出力を、横軸は飲食物の製造や出荷等の鮮度の基準となる日からの経過した日数を示している。また、Ｓt は鮮度の基準となる第一の飲食物の鮮度の基準となる日における測定値、Ｓa は鮮度を測定する対象である第二の飲食物の鮮度の基準となる日における測定値、Ｓt'は鮮度の基準となる第一の飲食物の所定日数経過後の測定値、Ｓa'は鮮度を測定する対象である第二の飲食物の所定日数経過後の測定値、Ｓa'' はＳa を線分Ｓt Ｓt'に平行に移動して求めた所定日数経過後の点である。
【００３４】
この図を用いて、前述の実施の形態について説明すると、第一の実施の形態では、鮮度の基準となる第一の飲食物をなるべく鮮度が落ちないような所定の条件で保存しているので、所定日数経過した時点での鮮度は、第二の飲食物としてサンプリングした飲食物の測定値Ｓa'とＳt'との差を目安とする。第二の実施の形態では、鮮度の基準となる第一の飲食物を保存せずにＳt を記憶しておいて、所定日数経過した時点での鮮度は、第二の飲食物としてサンプリングした飲食物の測定値Ｓa'とＳt との差を目安とする。この実施の形態では、第一の飲食物の劣化によるｙが測定結果に含まれない。第三の実施の形態では、｛（Ｓa'−Ｓt'）−（Ｓa −Ｓt ）｝、即ちｘを鮮度の目安とする。この実施の形態では、製造ロットの間に味の差（Ｓa −Ｓt ）があったとしても、｛（Ｓa'−Ｓt'）−（Ｓa −Ｓt ）｝を求めるので、全ロットについて第一の飲食物を準備する必要はない。第三の実施の形態も、第一の飲食物の劣化によるｙが測定結果に含まれてしまう。このｙが鮮度の測定に影響するような値になるものについては、次の第四の実施の形態のように、ｙについての補正を行う。
【００３５】
図７は、本発明の鮮度測定方法の第四の実施の形態での補正係数を求める回帰曲線を示す図である。図で、縦軸は味覚センサの出力、横軸は保存温度である。
飲食物としては、缶入りの緑茶を用いた。１０℃、２０℃、３０℃、４０℃、５０℃で３日間保存した緑茶をそれぞれ味覚センサで測定し、その測定値から図のような回帰曲線を求め、０℃や１℃の場合のｙを推定する。例えば、１℃のとき３日間で０．１ｍＶのセンサ出力だとすると、１℃３０日間では１ｍＶになる。
【００３６】
【発明の効果】
本発明によれば、両親媒性物質を含む分子膜を有する味覚センサを用いて飲食物の鮮度を測定することとしたから、測定時間が短くて済む、感度が官能検査に劣らない、評価が数値化できる飲食物の鮮度測定方法が提供できる。
【図面の簡単な説明】
【図１】本発明の鮮度測定方法の第一の実施の形態を示す流れ図である。
【図２】本発明の鮮度測定方法の第二の実施の形態を示す流れ図である。
【図３】本発明の鮮度測定方法の第三の実施の形態を示す流れ図である。
【図４】本発明の鮮度測定方法の第四の実施の形態を示す流れ図である。
【図５】本発明の鮮度測定方法の第一の実施の形態での実験結果を示す図である。
【図６】本発明の鮮度測定方法での各測定値の関係を示す図である。
【図７】本発明の鮮度測定方法の第四の実施の形態での補正係数を求める回帰曲線を示す図である。
【図８】脂質膜を化学物の設計で使われている表現方法で表した模式図である。
【図９】脂質膜を用いたセンサプローブの概略構成を示す断面図である。
【図１０】測定系を示す図である。
【図１１】測定手順を示す流れ図である。
【符号の説明】
１脂質膜
２脂質性分子
３脂質性分子群
４膜部材
５マトリックス
６センサプローブ
７基材（円筒）
８電極
９緩衝層
１０測定系
１１被測定溶液
１２容器
１３参照電極
１４緩衝層
１５リード線
１６リード線
１７バッファ増幅器
１８Ａ／Ｄ変換器
１９マイクロコンピュータ
２０Ｘ−Ｙレコーダ
２１シールド[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring the freshness of food and drink, and more particularly to a method for measuring the freshness of food and drink using a taste sensor.
[0002]
[Prior art]
The measurement of freshness of food and drink is performed by chemical analysis or the like, but it is not satisfactory in terms of measurement time and measurement sensitivity, and is mainly performed by sensory inspection.
[0003]
[Problems to be solved by the invention]
However, the sensory test has problems that there are individual differences in discrimination power, difficulty in digitizing evaluation, and poor objectivity.
The object of the present invention is to solve the above-mentioned problems, and to provide a method for measuring the freshness of foods and drinks, which requires a short measurement time, is not inferior to a sensory test, and can be evaluated numerically.
[0004]
[Means for Solving the Problems]
To solve the problems described above, the freshness measuring method of the present invention, the pump of Claim 1, measuring the freshness of food using a taste sensor with a molecular film containing amphipathic Substance freshness A method for storing a first food and drink serving as a reference for freshness under a predetermined condition, and immersing a taste sensor in the solution of the first food and drink stored under the predetermined condition Measuring the taste and obtaining a first measurement value; immersing the taste sensor in a solution of a second food or drink which is a target for measuring freshness; and measuring the taste to obtain a second measurement value; And determining the freshness of the second food and drink based on the difference between the first measurement value and the second measurement value.
[0005]
The pump of Claim 2, a freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphiphilic material quality of the first food as a reference of freshness Immersing a taste sensor in the solution to measure its taste to obtain a first measurement value and storing the first measurement value; and to the second food or drink solution to be measured for freshness, the taste The step of measuring the taste by immersing the sensor to obtain the second measured value, and the freshness of the second food and drink based on the difference between the stored first measured value and the second measured value The step of seeking.
[0006]
The pump of Claim 3, a freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphipathic Substance, the first food as a reference of freshness Before storing under a predetermined first condition, a taste sensor is immersed in the first food and drink solution to measure its taste to obtain a first measurement value, and a second object to measure freshness Before placing the food and drink under the second condition, immersing the taste sensor in the solution of the second food and drink to measure its taste and obtaining the second measured value, and the first food and drink And storing the taste sensor in a solution of the first food and drink stored under the first condition and measuring the taste to obtain a third measurement value. And immersing the taste sensor in a second food and drink solution placed under the second condition to measure its taste, And the freshness of the second food and drink based on the difference between the first measurement value and the second measurement value and the difference between the third measurement value and the fourth measurement value. The step of seeking.
[0007]
The pump of Claim 4, a freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphipathic Substance to be measured solution of the food to be measured Preparing a plurality of steps, storing the plurality of solutions to be measured at different temperatures for a predetermined time, and immersing the taste sensor in each of the plurality of solutions to be measured stored for a predetermined time to measure the taste thereof Obtaining a measurement value for each of the plurality of solutions to be measured; obtaining a regression curve related to the obtained plurality of measurement values and the temperature; and correcting freshness at a desired temperature based on the regression curve A value is obtained, and a correction value of freshness at a desired temperature after a desired time is multiplied by a correction value of freshness at a desired temperature obtained based on a regression curve by a value of the ratio between the desired time and the predetermined time, Asking for and A step of immersing a taste sensor in a solution of the first food and drink to measure the taste and obtaining a first measured value before storing the first food and drink serving as a reference for freshness under a predetermined first condition And before putting the second food and drink that is the object of measuring freshness under the second condition, the taste sensor is immersed in the solution of the second food and drink to measure its taste, and the second measured value , A step of storing the first food and drink under a predetermined first condition, and a taste sensor immersed in a solution of the first food and drink stored under the first condition To obtain a third measured value, and to measure the taste of the taste sensor by immersing the taste sensor in a second food or drink solution placed under the second condition. And obtaining the difference between the first measurement value and the second measurement value, the difference between the third measurement value and the fourth measurement value, and the correction value. There are and a step of determining the freshness of the second food.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Before describing the embodiment of the present invention, the taste sensor used in the present invention will be described.
The applicant of the present application previously filed a patent application regarding the invention of “taste sensor and its manufacturing method” in cooperation with others (Japanese Patent Laid-Open No. 3-54446). It was shown that a so-called lipid molecule group housed in a surface matrix with a specific molecular arrangement is a sensor that shows sensitivity to salty taste, sour taste, bitter taste, and sweetness, which are called basic tastes. Moreover, this type of sensor has been shown to be able to measure the taste instead of the human sense of taste.
[0009]
The high molecular polymer is, for example, polyvinyl chloride (PVC), and a mixture of a plasticizer such as dioctylphenyl phosphonate (DOPP) and a lipid in a weight ratio of approximately 2: 3: 1 is tetrahydrofuran ( THF), transferred to a flat-bottomed container, and kept on a plate at room temperature for 3 days to volatilize THF to obtain a lipid membrane, that is, a lipidic molecular membrane in which lipid is housed in the surface matrix of PVC. . The thickness of the film is about 200 μm.
[0010]
FIG. 8 shows a schematic diagram of a lipid molecular membrane expressed by the expression method used in the design method of chemicals. A spherical portion of the lipid molecule 2 indicated by a circle is a hydrophilic group a, that is, a hydrophilic part a, and has a hydrocarbon chain structure b (for example, an alkyl group) from which the atomic arrangement extends. In each of the figures, two chains extend to represent one molecule, and constitute a molecular group as a whole. This hydrocarbon chain part is a hydrophobic part b. Such a lipid molecule group 3 is partly dissolved in the matrix 5 (surface structure, micro structure having a planar expansion) on the surface of the membrane member 4 (for example, It is accommodated in 2 ') of FIG. Table 1 shows examples of lipids that can be used as raw materials for molecular films having such structures.
[0011]
[Table 1]

[0012]
Sensor probes using these lipid membranes are prepared.
FIG. 9 is a cross-sectional view showing a schematic configuration in which the lipid membrane 1 obtained as described above is processed into a sensor probe 6. A polyvinyl chloride cylinder having an outer shape of 8 mm, a length of 55 mm, and a wall thickness of 1 mm is used as the substrate 7. The tip 7a of the cylinder 7 is cut at an angle of about 60 degrees. The lipid membrane 1 is attached to the cut end portion 7a as an adhesive so as to close the opening 7b, and a solution of PVC in THF. An electrode 8 is formed by inserting a silver wire tip having a diameter of 0.5 mm in a spiral shape from the top of the cylinder 7. The buffer layer 9 is filled with an electrolytic solution (potassium chloride solution having a concentration of 3.3 mol / l) until the 8b is immersed in the spiral portion of the electrode 8.
[0013]
A taste measurement system using the sensor probe is shown in FIG.
The solution to be measured 11 is placed in a container 12 such as a beaker. The sensor probe 6 was placed in the solution to be measured 11. In this figure, one sensor probe is used, but when measuring by multichannel, a plurality of sensor probes having lipid membranes with different lipids (different responses to taste) are used. Prior to use, the electrode potential was stabilized with a 1 mmol / l aqueous solution of potassium chloride. A reference electrode 13 is prepared as an electrode for generating a potential serving as a measurement reference, and is put in the solution to be measured 11. The sensor probe 6 and the reference electrode 13 are installed with a predetermined distance therebetween. The surface of the reference electrode 13 is covered with a buffer layer 14 obtained by solidifying a saturated potassium chloride solution with agar.
[0014]
The electric signal from the lipid membrane 1 is guided to the buffer amplifier 17 by the lead wire 15 of FIG. The output of the buffer amplifier 17 is applied to the A / D converter 18. An electrical signal from the reference electrode 13 is also applied to the A / D converter 18 via the lead wire 16, and the difference from the potential from the lipid membrane 1 is converted into a digital signal. This digital signal is appropriately processed by the microcomputer 19 and displayed on the XY recorder 20.
[0015]
Next, an example of a measurement procedure using the taste sensor will be described with reference to FIG.
S1 The sensor potential V01 of the reference solution is measured.
In the case of batch-type measurement (measurement method in which the solution to be measured is performed for a beaker or the like), the sensor potential V01 of the reference solution is measured again after putting the taste sensor in and out a certain number of times. In the case of flow-type measurement (for example, a measurement method in which the solution to be measured and the reference solution are respectively flowed through the measurement pipe in which the taste sensor is set), after the reference solution is allowed to flow through the taste sensor for a certain time, the reference solution sensor is again Measure the potential V01.
S2 The sensor is immersed in the measured solution Si for a predetermined time and the sensor potential Vi of the measured solution Si is measured. The predetermined time is set in order to make the adsorption conditions the same for each solution to be measured Si.
S3 The measurement result ΔVi = Vi−V01 of the solution to be measured Si is calculated. Thereafter, when measuring the solution to be measured continuously, the process proceeds to S1.
[0016]
Incidentally, the lipid is a type of amphiphile, the amphiphilic substance other than a lipid shown in Table 2 can also be utilized in place of the lipid.
[0017]
[Table 2]

[0019]
It is possible to measure the freshness of food by using a taste sensor with a molecular film of the amphiphilic substance as described above.
[0020]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a flowchart showing a first embodiment of the freshness measuring method of the present invention, and corresponds to claim 1.
S11 is a step of storing the first food and drink serving as a reference for freshness under predetermined conditions.
The first food and drink is a food and drink that is stored to provide a value that serves as a reference for freshness. Therefore, the predetermined condition is, for example, 0 ° C. to 5 ° C. if the temperature of the first food or drink does not change as much as possible even if time elapses.
S12 is a step of obtaining a first measurement value St by immersing a taste sensor in the solution of the first food and drink stored under the predetermined condition and measuring its taste.
The first measured value St is a value serving as a reference for freshness.
S13 is a step of obtaining the second measurement value Si by immersing the taste sensor in a solution of a second food or drink, which is a target for measuring freshness, and measuring its taste.
S14 is a step of determining the freshness of the second food and drink based on the difference between the first measurement value and the second measurement value.
[0021]
Here, an experiment by the freshness measuring method of the first embodiment will be described.
The measurement object is a canned beverage marketed as a sports drink. As the taste sensor, an 8-channel (1ch to 8ch) taste sensor using 8 types of lipid membranes each containing a lipid shown in Table 4 was used.
[0022]
[Table 4]

[0023]
The reference liquid used was a sports drink stored under the same conditions as the sports drink used as a reference for freshness. Storage is performed in a refrigerator, and the temperature is 0 ° C. Sports drinks to be measured are those that have been placed for 1 week at a temperature of 30 ° C, those that have been placed for 2 weeks, those that have been placed for 1 week at a temperature of 50 ° C, and those that have been placed for 2 weeks. There are four types.
[0024]
The measurement procedure is as follows.
1) Immerse the taste sensor in a preservation solution (same as the reference solution) for approximately 10 hours.
2) Put the taste sensor in and out of the reference solution (for washing) 10 times and wash it.
3) Immerse the taste sensor in the reference solution (for measurement), measure the potential of the taste sensor after 10 seconds, and set the measured value to V0.
4) Repeat steps 2) and 3) twice or more, and for each measurement, determine whether the difference between the current measured value V0 and the previous measured value V0 is 0.3 mV or less, and 0.3 mV or less (that is, V0 is stable) If so, go to step 5).
5) Put the taste sensor 10 times in and out of a sports drink (for washing) which is a standard of freshness stored under a predetermined condition and wash it.
6) The taste sensor is immersed in a sports drink (for measurement) which is a reference for freshness stored under predetermined conditions, and the potential St of the taste sensor is measured after 10 seconds.
7) Put the taste sensor in and out of the sports drink (for washing) to be measured 10 times and wash it.
8) The taste sensor is immersed in a sports drink (for measurement) as a measurement target, and the potential Si of the taste sensor is measured after 10 seconds.
9) Repeat steps 2) to 8) a predetermined number of times.
[0025]
When the measured values thus obtained were subjected to principal component analysis, results as shown in FIG. 5 were obtained. In FIG. 5, PC1 represents the first main component, and PC2 represents the second main component.
It can be seen that under the conditions of 30 ° C. and 50 ° C., the points P31, P32, P51, and P32 corresponding to the freshness move away from the point P0 that serves as the freshness reference as time passes. Moreover, since the direction to go away differs, it turns out that the quality of deterioration differs on the conditions of 30 degreeC and 50 degreeC.
[0026]
FIG. 2 is a flowchart showing a second embodiment of the freshness measuring method of the present invention, and corresponds to claim 2.
S21 is a step of immersing the taste sensor in a solution of the first food and drink serving as a reference for freshness, measuring its taste, obtaining the first measured value St, and storing the first measured value St.
The first food and drink is a food and drink for providing a value that serves as a reference for freshness, and the first measured value St is a value that serves as a reference for freshness. In 2nd Embodiment, it is not required to preserve | save the 1st food / beverage on predetermined conditions like 1st Embodiment.
S22 is a step of obtaining a second measured value Si by immersing the taste sensor in a solution of a second food or drink, which is a target for measuring freshness, and measuring its taste.
S23 is a step of determining the freshness of the second food and drink based on the difference between the stored first measured value and the second measured value.
[0027]
FIG. 3 is a flowchart showing a third embodiment of the freshness measuring method of the present invention, and corresponds to claim 3.
S31 Before storing the first food and drink serving as a reference for freshness under a predetermined first condition, the taste sensor is immersed in the solution of the first food and drink to measure its taste, and the first measured value St is obtained. It is the stage to get.
The first food and drink is a food and drink that is stored to provide a value that serves as a reference for freshness. Therefore, the predetermined first condition is, for example, 0 ° C. to 5 ° C. if the temperature and the temperature of the first food and drink do not change as much as possible.
The first measured value St is a value serving as a reference for freshness.
S32 Before putting the second food or drink, which is the object of measuring freshness, under the second condition, the taste sensor is immersed in the solution of the second food or drink to measure its taste, and the second measured value Sa Is the stage to get. The second condition is, for example, a condition such as a temperature when the second food or drink is transported, stored in a warehouse, or arranged in a store.
S33 is a step of storing the first food and drink under predetermined conditions.
S34 is a step of obtaining a third measurement value St ′ by immersing the taste sensor in the solution of the first food and drink stored under the first condition and measuring its taste.
S35 is a step of obtaining a fourth measurement value Sa ′ by immersing the taste sensor in a solution of a second food or drink placed under the second condition and measuring its taste.
S36 The difference between the first measurement value and the second measurement value and the difference between the third measurement value and the fourth measurement value {(Sa'-St ')-(Sa-St)} And determining the freshness of the second food and drink based on the above.
[0028]
According to this method, even when there is a difference in taste that affects the measurement of freshness between production lots of food and drink, it is not necessary to store the first food and drink for all lots. It is enough to store food and drink as a representative. The difference in taste between lots is absorbed by calculating {(Sa'-St ')-(Sa-St)}.
[0029]
Here, an experiment by the freshness measurement method of the third embodiment will be described.
The measuring object is canned green tea. The taste sensor is an 8-channel (1ch to 8ch) taste sensor using eight types of lipid membranes each containing a lipid shown in Table 4 above. The reference liquid used was green tea stored under the same conditions as the green tea used as a reference for freshness. Storage is performed in a refrigerator, and the temperature is 1 ° C.
[0030]
The measurement procedure is as follows.
1) Immerse the taste sensor in a preservation solution (same as the reference solution) for approximately 10 hours.
2) Put the taste sensor in and out of the reference solution (for washing) 10 times and wash it.
3) Immerse the taste sensor in the reference solution (for measurement), measure the potential of the taste sensor 10 seconds later, and set the measured value as St.
4) Repeat steps 2) and 3) at least twice, and for each measurement, determine whether the difference between the current measured value St and the previous measured value St is 0.3 mV or less, and 0.3 mV or less (that is, St is stable) If so, go to step 5).
5) Put the taste sensor in and out of green tea (for washing) to be measured 10 times and wash it.
6) Immerse the taste sensor in the green tea (for measurement) to be measured, and measure the potential Sa of the taste sensor after 10 seconds.
7) After 30 days, the procedures 2) to 8) are repeated to obtain the measured value St ′ of the reference solution and the measured value Sa ′ of the green tea that is the measurement target. The green tea to be measured is placed under a condition (second condition) at a temperature of 50 ° C. for 30 days.
The freshness of green tea is highly correlated with {(Sa'-St ')-(Sa-St)}, and this value can be used as a measure of freshness.
[0031]
FIG. 4 is a flowchart showing a fourth embodiment of the freshness measuring method of the present invention, and corresponds to claim 4.
S41 is a step of preparing a plurality of solutions to be measured for foods and drinks to be measured.
S42 is a step of storing the plurality of solutions to be measured at different temperatures for a predetermined time.
S43 is a step of immersing the taste sensor for each of the plurality of solutions to be measured stored for a predetermined time and measuring the taste thereof to obtain measured values of the plurality of solutions to be measured.
S44 is a step of obtaining a regression curve related to the obtained plurality of measured values and the temperature.
S45 is a step of obtaining a freshness correction value at a desired temperature based on the regression curve.
S46 is a step for obtaining a freshness correction value at a desired temperature after a desired time by multiplying the freshness correction value at the desired temperature obtained based on the regression curve by the value of the ratio between the desired time and the predetermined time.
[0032]
S47 Before storing the first food and drink serving as a reference for freshness under a predetermined first condition, the taste sensor is immersed in the solution of the first food and drink to measure its taste, and the first measured value St is obtained. It is the stage to get.
The first food and drink is a food and drink that is stored to provide a value that serves as a reference for freshness. Therefore, the predetermined first condition is, for example, 0 ° C. to 5 ° C. if the temperature and the temperature of the first food and drink do not change as much as possible.
The first measured value St is a value serving as a reference for freshness.
S48 Before putting the second food / drink to be measured for freshness under the second condition, the taste sensor is immersed in the solution of the second food / drink to measure its taste, and the second measured value is obtained. It is the stage to get. The second condition is, for example, a condition such as a temperature when the second food or drink is transported, stored in a warehouse, or arranged in a store.
S49 is a step of storing the first food and drink under predetermined conditions.
S50 is a step of obtaining a third measurement value by immersing the taste sensor in the solution of the first food and drink stored under the first condition and measuring its taste.
S51 is a step of obtaining a fourth measurement value by immersing the taste sensor in a solution of a second food or drink placed under the second condition and measuring its taste.
S52: freshness of the second food based on the difference between the first measurement value and the second measurement value, the difference between the third measurement value and the fourth measurement value, and the correction value Is the stage of seeking.
[0033]
FIG. 6 is a diagram showing the relationship between each measurement value in the freshness measurement method of the present invention.
In the figure, the vertical axis indicates the output of the taste sensor, and the horizontal axis indicates the number of days that have elapsed since the date that is the basis for freshness such as the production and shipment of food and drink. In addition, St is a measured value on the day that is the standard of freshness of the first food and drink that is the standard of freshness, Sa is a measured value on the day that is the standard of freshness of the second food and drink that is the object of measuring freshness, St ′ is a measured value after elapse of a predetermined number of days of the first food and drink serving as a reference for freshness, Sa ′ is a measured value after elapse of a predetermined number of days of the second food and drink for which freshness is measured, This is a point after the passage of a predetermined number of days obtained by moving Sa in parallel with the line segment St St ′.
[0034]
The above-described embodiment will be described with reference to this figure. In the first embodiment, the first food and drink serving as a reference for freshness is stored under predetermined conditions so that the freshness is not reduced as much as possible. The freshness at the time when the predetermined number of days has elapsed is based on the difference between the measured values Sa ′ and St ′ of the food and drink sampled as the second food and drink. In the second embodiment, St is stored without storing the first food and drink serving as a reference for freshness, and the freshness at the time when a predetermined number of days have elapsed is the food and drink sampled as the second food and drink. The difference between the measured values Sa ′ and St of the object is used as a guide. In this embodiment, y due to deterioration of the first food or drink is not included in the measurement result. In the third embodiment, {(Sa'-St ')-(Sa-St)}, that is, x is used as a measure of freshness. In this embodiment, {(Sa'-St ')-(Sa-St)} is obtained even if there is a difference in taste (Sa-St) between production lots. There is no need to prepare food and drink. Also in the third embodiment, y due to deterioration of the first food and drink is included in the measurement result. For the value that y affects the measurement of freshness, the correction for y is performed as in the following fourth embodiment.
[0035]
FIG. 7 is a diagram showing a regression curve for obtaining a correction coefficient in the fourth embodiment of the freshness measurement method of the present invention. In the figure, the vertical axis represents the output of the taste sensor, and the horizontal axis represents the storage temperature.
Canned green tea was used as food and drink. Green tea stored at 10 ° C, 20 ° C, 30 ° C, 40 ° C and 50 ° C for 3 days is measured with a taste sensor, and a regression curve as shown in the figure is obtained from the measured value. Is estimated. For example, if the sensor output is 0.1 mV for 3 days at 1 ° C., it will be 1 mV for 30 days at 1 ° C.
[0036]
【The invention's effect】
According to the present invention, since it was decided to measure the freshness of food using a taste sensor with a molecular film containing amphipathic Substance, it requires only a short measurement time, the sensitivity is not inferior to sensory test, evaluation It is possible to provide a method for measuring the freshness of food and drink that can be quantified.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a first embodiment of a freshness measuring method of the present invention.
FIG. 2 is a flowchart showing a second embodiment of the freshness measuring method of the present invention.
FIG. 3 is a flowchart showing a third embodiment of the freshness measuring method of the present invention.
FIG. 4 is a flowchart showing a fourth embodiment of the freshness measuring method of the present invention.
FIG. 5 is a diagram showing an experimental result in the first embodiment of the freshness measuring method of the present invention.
FIG. 6 is a diagram showing the relationship between measured values in the freshness measuring method of the present invention.
FIG. 7 is a diagram showing a regression curve for obtaining a correction coefficient in the fourth embodiment of the freshness measurement method of the present invention.
FIG. 8 is a schematic diagram showing a lipid membrane in an expression method used in the design of chemicals.
FIG. 9 is a cross-sectional view showing a schematic configuration of a sensor probe using a lipid membrane.
FIG. 10 is a diagram showing a measurement system.
FIG. 11 is a flowchart showing a measurement procedure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lipid membrane 2 Lipid molecule 3 Lipid molecule group 4 Membrane member 5 Matrix 6 Sensor probe 7 Base material (cylinder)
8 Electrode 9 Buffer layer 10 Measurement system 11 Solution to be measured 12 Container 13 Reference electrode 14 Buffer layer 15 Lead wire 16 Lead wire 17 Buffer amplifier 18 A / D converter 19 Microcomputer 20 XY recorder 21 Shield

Claims

A freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphiphilic material quality step of storing a first food as a reference of freshness under predetermined conditions (S11 ), A step of immersing the taste sensor in the solution of the first food and drink stored under the predetermined condition to measure its taste to obtain a first measurement value (S12), and an object for measuring freshness A step of obtaining the second measurement value by immersing the taste sensor in a solution of a second food and drink to obtain a second measurement value (S13), and the difference between the first measurement value and the second measurement value. And a step (S14) of determining the freshness of the second food based on the freshness measurement method.

A freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphiphilic material quality thereof by immersing the taste sensor in a solution of a first food as a reference of freshness Measuring the taste, obtaining a first measured value and storing the first measured value (S21); immersing the taste sensor in a solution of a second food or drink which is a target for measuring freshness; A step of measuring taste and obtaining a second measured value (S22), and a step of determining the freshness of the second food and drink based on the difference between the stored first measured value and the second measured value ( S23).

A freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphipathic Substance stores the first food as a reference of freshness at a predetermined first condition A step (S31) of obtaining a first measurement value by immersing a taste sensor in the solution of the first food and drink to obtain a first measurement value, and a second food and drink to be measured for freshness second Before placing the taste sensor in the solution of the second food and drink, and measuring the taste to obtain a second measured value (S32) before placing the first food and drink in a predetermined condition. A step of storing under the first condition (S33) and a step of immersing the taste sensor in the solution of the first food and drink stored under the first condition to measure its taste to obtain a third measured value (S34) and measuring the taste by immersing the taste sensor in a solution of the second food and drink placed under the second condition Obtaining a fourth measurement value (S35), based on the difference between the first measurement value and the second measurement value, and the difference between the third measurement value and the fourth measurement value; The freshness measuring method including the step (S36) of obtaining the freshness of the second food and drink.

A freshness measuring method for measuring the freshness of food using a taste sensor with a molecular film containing amphipathic Substance, and step (S41) a plurality preparing the measured solution of the food is measured, Storing the plurality of solutions to be measured at different temperatures for a predetermined time (S42); immersing the taste sensor for each of the plurality of solutions to be measured stored for a predetermined time; measuring the taste; Obtaining a measured value of each measured solution (S43), obtaining a regression curve related to the obtained plurality of measured values and the temperature (S44), and at a desired temperature based on the regression curve A step of obtaining a freshness correction value (S45), and a freshness correction value at a desired temperature after a desired time, and a freshness correction value at a desired temperature obtained based on a regression curve to the ratio of the desired time and the predetermined time Multiply the value to obtain the step (S46) and immerse the taste sensor in the first food / drink solution before storing the first food / drink serving as a freshness reference under the predetermined first condition. Measuring the taste and obtaining the first measured value (S47), and tasting the second food / drink solution before placing the second food / drink subject to freshness measurement under the second condition A step of immersing the sensor to measure its taste to obtain a second measured value (S48), a step of storing the first food and drink under a predetermined first condition (S49), and the first condition Immersing the taste sensor in the solution of the first food and drink stored in step (3) to measure the taste to obtain a third measurement value (S50), and the second placed under the second condition. Immersing the taste sensor in a food and beverage solution to measure its taste to obtain a fourth measured value (S51), and the first measured value, The step of obtaining the freshness of the second food and drink based on the difference between the second measured value, the difference between the third measured value and the fourth measured value, and the correction value (S52) Including freshness measurement method.